Henning,
First make sure you actually have multiple instances and not multiple
workbooks open in the same instance.
Check the setting ToolsOptionsViewWindows in Taskbar.

If you are working in the same instance, it is more simple:
Dim WB as workbook

set wb=workbooks("SomeWorkbook.xls")

Otherwise look in GetObject.

You can use the Windows API, but automation/COM is more straight forward.
But depends on your situation/requirements.

NickHK

"Henning Winkler" wrote in message
ps.com...
Hi all,

I'm looking for a way, to catch a specific excel instance and use
their objects (fill in data f.e.) . I my case, there are several
excels (listed in the taskbar) - f.e.five - and I want to access the
instance with the title "Microsoft Excel - Test1.xls.". I tried that
with findwindow-api, but I think, a can't acess the excel object via
this window handle, right ?
Any idea to solve this problem ?

Thanks in advance

Henning